Embroidery frame transfer device

ABSTRACT

An embroidery frame transfer device including an embroidery frame holding a workpiece cloth; a carriage supporting the embroidery frame by detachable attachment; a Y-direction transfer mechanism having a first and second ends that moves the carriage in a first direction represented as a Y-direction; an X-direction transfer mechanism that supports the first end from below and that transfers the Y-direction transfer mechanism in a second direction represented as an X-direction orthogonal to the Y-direction; a cover element containing the X-direction transfer mechanism and having an upper surface situated below the Y-direction transfer mechanism; a support structure provided at the second end and that is placed in contact with the upper surface of the cover element to support the Y-direction transfer mechanism; and an elastic element pressing the support structure against the cover element such that the support structure maintains contact with the upper surface of the cover element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application 2008-315641, filed on Dec. 11, 2008, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to an embroidery frame transfer device.

BACKGROUND

Embroidery frame transfer devices have been known that are detachably attached to sewing machines. Such embroidery frame transfer devices typically embroider a workpiece cloth by holding the workpiece cloth with an embroidery frame and transferring the embroidery frame in X and Y directions. A typical embroidery frame transfer device is provided with a carriage, an X-direction transfer mechanism and a Y-direction transfer mechanism. The carriage allows detachable attachment of the embroidery frame. The X-direction transfer mechanism transfers the carriage in the X direction in alignment with the lengthwise direction of the sewing machine bed, whereas the Y-direction transfer mechanism transfers the carriage in the Y direction orthogonal to the X direction. Thus, the desired embroidery patterns can be formed on the workpiece cloth using a sewing machine by attaching the embroidery frame holding the workpiece cloth to the carriage and transferring the embroidery frame and the carriage in the X and Y directions by the X-direction transfer mechanism and the Y-direction transfer mechanism.

The problem with such embroidery frame transfer device is that the Y-direction transfer mechanism is supported only at one side, more specifically at its lengthwise front side by the X-direction transfer mechanism to exhibit a so-called cantilever structure. Thus, the vibration caused by carriage transfer is prone to become greater in magnitude towards the rear end side of the Y-direction transfer mechanism which is on the opposite side of the front side where it is supported by the X-direction transfer mechanism. Thus, the embroidery frame attached to the carriage suffers greater vibration at the rear end side of the Y-direction transfer mechanism and at the opposite side of the carriage attachment, in other words, at the far side relative to the carriage attachment. The problem with such vibrations is that it disturbs, though slightly, the stitching process to cause irregularities in the embroidery pattern formed on the workpiece cloth attached to the embroidery frame.

To address such problem, a protrusion may be provided at the rear side of the Y-direction transfer mechanism and the protrusion may be placed in contact with the upper surface of a cover of the X-direction transfer mechanism to provide support at the rear end side of the Y-direction transfer mechanism. However, the provision of such protrusion is not a comprehensive solution in eliminating the irregularities in the embroidery patterns because it fails to mitigate vibration of the Y-direction transfer mechanism when the protrusion is detached from the upper surface of the cover by vertical vibration.

SUMMARY

An object of the present disclosure is to provide an embroidery frame transfer device that reduces the vibration of the Y-direction transfer mechanism and the embroidery frame driven by it to consequently reduce the irregularities/misalignments in the embroidery pattern to an ignorable level.

In one aspect of the present disclosure, an embroidery frame transfer device includes an embroidery frame that holds a workpiece cloth; a carriage that supports the embroidery frame by detachable attachment; a Y-direction transfer mechanism that has a first end and a second end and that moves the carriage in a first direction represented as a Y-direction; an X-direction transfer mechanism that supports the first end of the Y-direction transfer mechanism from below and that transfers the Y-direction transfer mechanism in a second direction represented as an X-direction orthogonal to the Y-direction; a cover element that contains therein the X-direction transfer mechanism and that has an upper surface situated below the Y-direction transfer mechanism; a support structure provided at the second end of the Y-direction transfer mechanism and that is placed in contact with the upper surface of the cover element to support the Y-direction transfer mechanism; and an elastic element that presses the support structure against the cover element such that the support structure maintains contact with the upper surface of the cover element.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present disclosure will become clear upon reviewing the following description of the illustrative aspects with reference to the accompanying drawings, in which,

FIG. 1 is a perspective view of a sewing machine with an attachment of embroidery frame transfer device according to a first exemplary embodiment of the present disclosure;

FIG. 2 is a plan view depicting the overall view of the embroidery frame transfer device;

FIG. 3 is a cross sectional view taken along line of FIG. 2;

FIG. 4 is an enlarged cross sectional view of a support structure shown in FIG. 3;

FIG. 5 is a perspective view depicting the overall configuration of the support structure of the embroidery frame transfer device according to the first exemplary embodiment of the present disclosure;

FIG. 6 depicts the overall configuration of the support structure of the embroidery frame transfer device according to the first exemplary embodiment of the present disclosure as viewed from the right side;

FIG. 7 depicts the support structure as viewed from the front side indicated by the arrow given in FIG. 6;

FIG. 8 depicts the support structure as viewed from the downward direction indicated by the arrow given in FIG. 6;

FIG. 9 is a schematic view showing the relative positioning of a support shaft to a roller shaft of the support structure;

FIG. 10 is a schematic view showing the relative positioning of the support shaft and the roller shaft of the support structure to the centroid of a Y-direction transfer mechanism;

FIG. 11 is a schematic view of an embroidery pattern sewn by the embroidery frame transfer device according to the first exemplary embodiment of the present disclosure;

FIG. 12 is a top view depicting the overall configuration of the embroidery frame transfer device according to the first exemplary embodiment of the present disclosure;

FIG. 13 is a descriptive view indicating the sequence of forming embroidery pattern shown in FIG. 11;

FIG. 14 schematically depicts an embroidery pattern sewn with a conventional embroidery frame transfer device;

FIG. 15 depicts the overall configuration of the support structure according to a second exemplary embodiment of the present disclosure; and

FIG. 16 depicts the overall configuration of the support structure according to a third exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

With reference to the drawings, a description will be given hereinafter on multiple exemplary embodiments of the present disclosure in which an embroidery frame transfer device according to the present disclosure is applied to a household sewing machine hereinafter simply referred to as a sewing machine. The following description will be based on the assumption that front and rear, left and right, and up and down directions given in FIG. 1 indicates the respective direction as viewed from the sewing machine. For instance, the left and right direction corresponds to the second direction or the X direction, the front and rear direction or the back and forth direction as the first direction or the Y direction, and the up and down direction as the Z direction.

Next, a description will be given hereinafter on sewing machine 11 provided with embroidery frame transfer device 10 shown in FIG. 1. Referring to FIG. 1, sewing machine 11 includes bed 12, pillar 13, arm 14, and head 15. Though not shown in detail, head 15 contains components such as a needle bar, a presser bar and presser foot 17. Embroidery frame transfer device 10 is detachably attached on bed 12. The needle bar and the presser bar are supported vertically movably by head 15. The needle bar has a sewing needle not shown provided at its lower end, whereas the presser bar has presser foot 17 at its lower end for embroidery stitching. Bed 12 contains a rotary shuttle not shown that serves as a loop taker.

Sewing machine 11 is further provided with drive mechanisms such as a sewing machine motor not shown, a needle bar drive mechanism that drives the needle bar, a thread take-up, a thread take-up drive mechanism that drives the thread take-up, and a shuttle drive mechanism that drives the rotary shuttle. These drive mechanisms are driven by the sewing machine motor such that the needle bar, the thread take-up, and the rotary shuttle are driven in coordination. Thus, the sewing needle attached to the bottom end of the needle bar, the thread take-up, and the rotary shuttle cooperate in forming stitches on the workpiece cloth.

Next, a description will be given on embroidery frame transfer device 10. As shown in FIGS. 1 to 3, embroidery frame transfer device 10 is provided with embroidery frame 21, carriage 22, Y-direction transfer mechanism 23, and X-direction transfer mechanism 24. Embroidery frame 21 is provided with a connector 25 that is disconnectably connected to carriage 22. Carriage 22 supports embroidery frame 21 through connector 25. Y-direction transfer mechanism 23 transfers carriage 22 back and forth in the Y direction which is the width direction of bed 12. X direction transfer mechanism 24 is provided below the Y direction transfer mechanism 23 and transfers carriage 22 along with Y-direction transfer mechanism 23 in the left and right direction, in this case, the lengthwise direction of bed 12 or the X direction.

Embroidery frame transfer device 10 is provided with cover 27 that contains X-direction transfer mechanism 24 within it. Cover 27 has a smooth upper surface 28. Y-direction transfer mechanism 23 is enclosed in a case 31. Case 31 is provided immediately above cover 27 and is elongated in the front and rear direction such that its front and rear ends extend beyond the front and rear ends of cover 27.

Though not shown in detail, when embroidery frame transfer device 10 is attached to bed 12, upper surface 28 of cover 27 is at level with the upper surface of bed 12 to be coplanar with bed 12.

Embroidery frame 21 comprises a connector 25 and frame section 35 which receives the workpiece cloth. Connector 25 is connected to carriage 22. Embroidery frame 21 comes in different sizes and shapes other than the type shown in FIG. 1. Frame section 35 comprises outer frame 36, inner frame 37, and fastener 38 for fastening outer frame 36 and inner frame 37 together. The workpiece cloth is mounted on frame section 35 of embroidery frame 21 by being clamped between outer frame 36 and inner frame 37 which are tightened together by fastener 38.

As shown in FIG. 3, X-direction transfer mechanism 24 is provided with X-direction guide shaft 41 that extends in the left and right direction. Both the left and right ends of X-direction guide shaft 41 are secured on a base frame not shown provided inside cover 27. Y-direction transfer mechanism 23, on the other hand, is provided with Y-direction guide shaft 42 that extends in the front and rear direction. Both the front and rear ends of Y-direction guide shaft 42 are secured on Y-direction frame 71 provided inside case 31. Carriage 22 being supported by Y-direction guide shaft 42 is transferred in the front and rear direction, that is, the Y-direction.

X-direction transfer mechanism 24 is provided with X-direction frame 43 which is movable along X-direction guide shaft 41. X-direction frame 43 is provided with a first protrusion protruding forward from guide groove 45 which is provided on front wall 44 of cover 27 and a second protrusion protruding upward from guide groove 46 provided on upper surface 28 of cover 27. The first and the second protrusions are connected to the underside of Y-direction frame 71. Guide groove 45 is defined on front wall 44 of cover 27 so as to run in the left and right direction, whereas guide groove 46 is defined on upper surface 28 of cover 27 so as to run in the left and right direction.

X-direction frame 43 is driven by a drive mechanism not shown, so as to be transferred in the X direction along X-direction guide shaft 41. Thus, Y-direction frame 71 is moved in the X direction integrally with X-direction frame 43.

Y-direction transfer mechanism 23 is provided with a drive mechanism not shown that moves carriage 22 in the Y direction. Thus, carriage 22 being supported by Y-direction guide shaft 42 is driven so as to be transferred in the Y-direction.

Carriage 22 having embroidery frame 21 attached to it is driven in the X and Y directions by X-direction transfer mechanism 24 and Y-direction transfer mechanism 23, respectively. As a result, the workpiece cloth mounted on embroidery frame 21 is moved to the left and right and back and forth with embroidery frame 21.

Embroidery frame transfer device 10 is provided with a support structure 50. Support structure 50 provides support at rear end 33 side of Y-direction transfer mechanism 23 which is not supported by X-direction transfer mechanism 24. As shown in FIGS. 4 to 8, support structure 50 comprises roller 51, roller shaft 52, support frame 53, support shafts 54 and 55, and upper frame 56. Roller 51 is pivoted about rotary shaft 52. Support frame 53 supports the two extreme ends of roller shaft 52. On the line of extension from the two extreme ends of roller shaft 52, support shafts 54 and 55 are provided, respectively. That is, the two support shafts 54 and 55 are provided on the line of extension which is the axial extension of the shaft center of roller shaft 52. Support shafts 54 and 55 provide support to support frame 53 so that it can be moved up and down in the Z direction relative to upper frame 56.

Both support shafts 54 and 55 have one end, in this case, the lower end secured to support frame 53. Of the two shafts, support shaft 54 is secured to support frame 53 by calking or press fitting. Support shaft 55, on the other hand, has a male thread section formed at its tip that is screw engaged with a female thread hole not shown formed at support frame 53 to be secured by screw engagement to support frame 53. The male thread section formed at the tip of support shaft 55 is tightened by nut 57 to prevent loosening of support shaft 55 relative to support frame 53. Such loosening of support shaft 55 may be prevented alternatively by a thread locking agent instead of nut 57. As shown in FIG. 5, the remaining other end of support shaft 54, in this case, the upper end, passes through opening 58 of upper frame 56, whereas the upper end of support shaft 55 passes through opening 59 of upper frame 56. On the upper ends of support shafts 54 and 55, stop rings 61 and 62 are mounted respectively to prevent support shafts 54 and 55 from dropping off of upper frame 56.

As shown in FIGS. 4 to 8, support frame 53 has a central curvature 63 that protrudes upward relative to its front and rear ends, in other words, the Y-directional ends. Roller 51 is provided so as to be embraced by curvature 63. Curvature 63 of support frame 53 is provided with a pair of walls that supports roller shaft 52. The axial ends of roller shaft 52 are supported by walls 64 and 65 respectively and are further secured by stop rings 521 and 522. Roller 51 is thus, supported rotatably relative to roller shaft 52 but unmovably relative to support frame 53. Roller 51 is equally spaced from support shaft 54 and support shaft 55 so that roller 51 is situated in the middle of support shaft 54 and support shaft 55. Thus, roller 51 is supported steadily between support shafts 54 and 55 by support frame 53.

Embroidery frame transfer device 10, more specifically, support shaft 54 and support shaft 55 have elastic elements, in this case, coil springs 66 and 67 wound on their outer periphery which are each situated between support frame 53 and upper frame 56. The elastic element may come in any form other than coil spring such as leaf spring, rubber, and urethane foam. Both coil springs 66 and 67 urge support frame 53 and upper frame 56 away from each other. Thus, roller 51 supported by roller 53 is also urged away from upper frame 56, in this case, downward.

Upper frame 56 has a projection 68 that projects leftward as shown in FIGS. 5, 7, and 8. As shown in FIG. 4, Y-direction frame 71 is provided with a recess 72 for accommodating support structure 50. Thus, support structure 50 is mounted at the underside of Y-direction frame 71 as shown in FIGS. 3 and 4. The underside of projection 68 of is placed in contact with the upper surface of Y-direction frame 71. Projection 68 is provided with protrusion 73 that protrudes downward, that is, toward support frame 53 as viewed in FIGS. 6 to 8 in an annular form. Protrusion 73 is fitted into a fitting hole not shown formed on Y-direction frame 71 to locate Y-direction frame 71 with support structure 50. Projection 68, that is, upper frame 56 is secured on Y-direction frame 71 by a screw not shown which is placed in screw engagement with a thread hole formed on Y-direction frame 71 through hole 74 defined on projection 68.

As earlier described, the lower end of support shaft 55 is screw engaged with support frame 53. Support shaft 55 is engaged with support frame 53 after roller 51 and roller shaft 52 are installed within curvature 63 to eliminate any possibility of interference with support shaft 55 during the installation of roller 51 and roller frame 52. The above described sequence of installation facilitates the mounting of roller 51 and roller shaft 52 into curvature 63 situated between support shaft 54 and support shaft 55 even when the spacing between the support shaft 54 and support shaft 55 is narrow. As a result, neither the spacing between support shaft 54 and support shaft 55 nor the size of support frame 53 need to be increased to provide ease in the installation of roller 51 and roller shaft 52. Thus, downsizing of roller 51 and roller shaft 52 can be facilitated to consequently allow downsizing of support structure 50.

By employing the above described configuration of screw engaging support shaft 55 with support frame 53, installation of roller 51 and roller shaft 52 within curvature 63 can be facilitated while allowing the spacing between support shaft 54 and support shaft 55 to be reduced. The slanting of roller shaft 52 supported by support frame 53 is reduced as the distance between support shaft 54 and support shaft 55 becomes smaller. Thus, the above described configuration yields downsizing of support structure 50 and steady rotation of roller 51 at the same time.

According to the above described configuration, roller 51 of support structure 50 and support frame 53 that supports roller shaft 52 are pressed downward by coil springs 66 and 67. As shown in FIG. 4, since upper surface 28 of cover 27 is situated below support structure 50, roller 51 is consequently pressed against upper surface 28 of cover 27. Thus, when Y-direction transfer mechanism 23 moves above cover 27 in the X-direction, roller 51 of support section 50 in rotation moves along upper surface 28 of cover 27 along with Y-direction transfer mechanism 23. On the outer periphery of roller 51, ring 75 is provided for anti-vibration purpose. Ring 75, being annularly shaped as an O-shaped ring, for example, circumferentially covers the outer periphery of roller 51. Ring 75 is made of elastic material such as rubber and resin foam to absorb the vibration when roller 51 rolls over upper surface 28 of cover 27.

As shown in FIG. 9, the centers of support shafts 54 and 55 and the center of roller shaft 52 is collinear with imaginary straight line L1. As shown in FIG. 10, imaginary centroidal line L2 extending in the Y direction and passing through centroid, in other words, center of gravity D of Y-direction transfer mechanism 23 is parallel to the aforementioned imaginary straight line L1 which passes through the centers of support shafts 54 and 55 and roller shaft 54, both of which lines L1 and L2 reside on Y-Z plane 100. In other words, imaginary straight line L1 and centroidal line L2 residing on Y-Z plane 100 which extends in the Z-direction, in other words, the up and down direction are parallel and imaginary straight line L1 is gravitationally below centroidal line L2. Thus, by disposing imaginary straight line L1 below centroidal line L2 in parallel on Y-Z plane 100, the centers of support shaft 54 and support shaft 55 and the center of roller shaft 52 are both situated immediately below and in close proximity of centroidal line L2 passing through centroid D of Y-direction transfer mechanism 23. This means that support structure 50 supports centroid D of Y-direction transfer mechanism 23 at the optimal position to improve the balance of Y-direction transfer mechanism 23. Roller 51 of support structure 50 is disposed as far as possible in the Y-direction from the portion where Y-direction transfer mechanism 23 is supported by X-direction frame 43 and is disposed at a position to contact upper surface 28 of cover 27. Thus, support structure 50 supports Y-direction transfer mechanism 23 to allow its smooth and steady movement in the X direction.

Next, a description will be given on the operation of embroidery frame transfer device 10 according to the above described configuration.

Y-direction transfer mechanism 23 is supported by X-direction frame 43 at its front end 32 side. Thus, Y-direction transfer mechanism 23 takes the so called cantilever structure in which one of the lengthwise ends is supported by X-direction frame 43. On the other hand, rear end 33 side of Y-direction transfer mechanism 23 in the opposite side of X-direction frame 43 is supported by support structure 50. Thus, by supporting rear end 33 side of Y-direction transfer mechanism 23 by support structure 50, vibration, if any, occurring at Y-direction transfer mechanism 23 when transferring carriage 22 is absorbed by support structure 50 being movable in the Z-direction, which in turn reduces the vibration occurring at embroidery frame 21 supported by carriage 22. As a result, irregularities observed in the embroidery pattern sewn on the workpiece cloth, is generally reduced to an ignorable level.

One example of the embroidery pattern is schematically shown in FIG. 11. Embroidery pattern 80 shown in FIG. 11, in this case, is sewn at the right side rear end portion of embroidery frame 21 as shown in FIG. 12. As shown in FIG. 13, formation of embroidery pattern 80 is started from embroidery start position S and proceeds in the sequence of (1) and (2) to form partial patterns 81 and 82 and thereafter (3) to (10) to form partial patterns 83 to 90 comprising radially extending straight lines. Each of the partial patterns are shown with spacing between them for providing good visibility and for ease of explanation, however, in the actual embroidery pattern, the partial patterns are sewn in the forward direction and then in the rearward returning direction such that the rearward stitches overlap with the forward stitches.

Carriage 22 that supports embroidery frame 21 is supported by Y-direction transfer mechanism 23 which is supported at its forward end 32 side by X-direction frame 43. Thus, as can be seen in FIG. 12, embroidery frame 21 suffers relatively greater vibration at its right side rear end portion and slight irregularities or misalignment are observed in the embroidery pattern in which forward stitches and rearward stitches are supposed to overlap. FIG. 14 schematically shows embroidery pattern 101 sewn under the conventional configuration, that is, an embroidery frame transfer device in which Y-direction transfer mechanism 23 is supported at its front end 32 side by X-direction frame 43 but its rear end 33 side is not supported by support structure 50. When embroidery pattern 101 is compared with embroidery pattern 80 shown in FIG. 11 sewn by embroidery frame transfer device 10 according to the first exemplary embodiment of the present disclosure, the partial patterns which should overlap are slightly spaced away.

Contrastingly, according to the first exemplary embodiment, Y-direction transfer mechanism 23 has its rear end 33 side supported by support structure 50 while support frame 53 that supports roller 51 is pressed against upper surface 28 of cover 27 by coil springs 66 and 67. Thus, even if vibration occurs when Y-direction transfer mechanism 23 is transferred in the X-direction, the vibration is absorbed by the Z-directional movement of support frame 53 that supports roller 51 and by extension and contraction of coil springs 66 and 67. As a result, vibration of rear end 33 side of Y-direction transfer mechanism 23 is reduced whereby the vibration of embroidery frame 21 supported by Y-direction transfer mechanism 23 through carriage 22 is reduced. Thus, embroidery pattern 80 shown in FIG. 11 has relatively less irregularities or misalignments compared with the conventional example shown in FIG. 14, and in the embroidery patterns actually sewn, such irregularities and misalignment is hardly recognizable when thread thickness and puckering, etc. is taken into consideration.

Embroidery frame transfer device 10 according to the above described first exemplary embodiment has the following effects.

Embroidery frame transfer device 10 is provided with support structure 50 which allows rear end side 33 of Y-direction transfer mechanism 23 to be supported by cover 27. Support structure 50 is pressed against cover 27 by coil springs 66 and 67. Thus, variation in vertical distance between Y-direction transfer mechanism 23 and cover 27 caused by vibration can be absorbed by the Z direction movement of roller 51 induced by coil springs 66 and 67. Accordingly, the vibration of Y-direction transfer mechanism 23 and consequently the vibration of embroidery frame 21 can be reduced so that irregularities in the resulting embroidery pattern can be minimized to an ignorable level.

By employing coil springs 66 and 67, support structure 50 can be reduced in complexity and cost and at the same time allow support structure 50 to be pressed against cover 27 with greater reliability.

Support structure 50 is primarily configured by roller 51 that moves along upper surface 28 of cover 27 by rolling. Thus, friction generated during the movement can be reduced by employing a roller configuration to allow smooth movement of Y-direction transfer mechanism 23.

Roller 51 is provided with anti-vibration ring 75 on its outer periphery. Ring 75 being made of flexible material such as rubber and foam resin is formed into an annular shape to circumferentially cover the outer periphery of roller 51. Thus, ring 75 absorbs the vibration generated during the movement of roller 51 to consequently reduce the vibration of Y-direction transfer mechanism 23 more effectively.

Support structure 50 is configured to support roller shaft 52, which rotatably supports roller 51 between a couple of support shafts 54 and 55, in cooperation with support frame 53. According to such configuration, the Z-directional dimension can be reduced while maintaining sufficient amount of movement of roller 51 in the up and down direction, in other words, the Z direction and at the same time helps keeping Y-direction transfer mechanism 23 compact. Thus, roller 51 is allowed to move in sufficient amounts without having to increase the size of Y-direction transfer mechanism 23.

Support structure 50 is configured such that the centers of the two support shafts 54 and 55 and the center of roller shaft 52 are collinear with imaginary straight line L1. Further, imaginary straight line L1 and centroidal line L2 passing through centroid D of Y-direction transfer mechanism 23 are parallel on plane Y-Z 100 on which centroidal line L2 resides. Thus, support structure 50 for supporting Y-direction transfer mechanism 23 is disposed at the optimal position for supporting Y-direction transfer mechanism 23 at its centroid D. Hence, Y-direction transfer mechanism 23 can be further supported with more stabilized balance by support structure 50 to reduce the vibration of Y-direction transfer mechanism 23.

Next, a description will be given on the support structure of the embroidery frame transfer device according to second and third exemplary embodiments with reference to FIGS. 15 and 16. The elements that are substantially identical to the first exemplary embodiment will be identified with identical reference symbols and will not be explained.

According to the second exemplary embodiment, support structure 150, as shown in FIG. 15 is provided with roller 151, roller shaft 152, and support frame 153. Support frame 153 supports the extreme ends of roller shaft 152 that penetrate roller 151. Thus, roller 151 is supported rotatably relative to roller shaft 152 but unmovably relative to support frame 153. Embroidery frame transfer device 10 is provided with coil spring 154. Coil spring 154 has one end secured to engagement portion 155 of Y-direction frame 71 and the remaining other end secured to support frame 153. Coil spring 154 is secured to support frame 153 so as to be situated at the end opposite the end to which roller 151 is provided. Support frame 153 has a hole 156 defined at a portion situated between the end on which roller 151 is provided and the end on which coil spring 154 is provided. Hole 156 has support element 157 supported by Y-direction frame 71 inserted into it. Support frame 153 is thus allowed to swing about support element 157.

Elasticity of coil spring 154 operates in the direction to contract itself or reduce its length, thus, pulling up the end of support frame 153. As a result, roller 151 of support structure 150 is pressed against upper surface 28 of cover 27.

The second exemplary embodiment provides, in addition to the effects of the first exemplary embodiment, support structure 150 which is even more simplified in structure as compared with the first exemplary embodiment. Thus, support structure 150 can be made of relatively less parts and in smaller size.

According to the third exemplary embodiment, as shown in FIG. 16, support structure 250 is provided with roller 251, roller shaft 252, support frame 253, and support shaft 254. Roller 251 is supported rotatably by roller shaft 252. Support frame 253 supports the extreme ends of roller shaft 252 that penetrate roller 251. Thus, roller 251 is supported rotatably relative to roller shaft 252 but unmovably relative to support frame 253. Embroidery frame transfer device 10 is provided with coil spring 255. Coil spring 255 has support shaft 254 passed through its inner peripheral side and has one of its ends placed in contact with the underside of Y-direction frame 71 and its other end placed in contact with the upper surface of support frame 253. Support shaft 254 is formed integrally with support frame 253 so as to extend upward from support frame 253. Support shaft 254 is passed through hole 256 defined on Y-direction frame 256. Thus, support shaft 254, support frame 253 and roller 251 supported by support frame 253 are allowed to move integrally up and down, in other words, in the Z-direction.

Elasticity of coil spring 255 operates in the direction to expand itself or increase its length, thus, pressing support roller 251 downward through support frame 253. As a result, roller 251 supported by support frame 253 is pressed against upper surface 28 of cover 27 by the pressure exerted by coil spring 255.

The third exemplary embodiment provides, in addition to the effects of the first exemplary embodiment, support structure 250 which is simplified in structure as compared with the first exemplary embodiment as was the case in the second exemplary embodiment. Thus, support structure 250 can be made with even less parts and in even smaller size.

In the above described exemplary embodiments, descriptions have been given on structures that support rollers 51, 151, and 251 by roller shafts 52, 152, and 252. However, instead of the above described configuration, the roller and the roller shaft may be molded integrally, or the roller shaft may be press fitted/insert molded into the roller, to allow the integral assembly of roller and roller shaft to be supported rotatably by the support frame.

While various features have been described in conjunction with the examples outlined above, various alternatives, modifications, variations, and/or improvements of those features and/or examples may be possible. Accordingly, the examples, as set forth above, are intended to be illustrative. Various changes may be made without departing from the broad spirit and scope of the underlying principles. 

1. An embroidery frame transfer device, comprising: an embroidery frame that holds a workpiece cloth; a carriage that supports the embroidery frame by detachable attachment; a Y-direction transfer mechanism that has a first end and a second end and that moves the carriage in a first direction represented as a Y-direction; an X-direction transfer mechanism that supports the first end of the Y-direction transfer mechanism from below and that transfers the Y-direction transfer mechanism in a second direction represented as an X-direction orthogonal to the Y-direction; a cover element that contains therein the X-direction transfer mechanism and that has an upper surface situated below the Y-direction transfer mechanism; a support structure provided at the second end of the Y-direction transfer mechanism and that is placed in contact with the upper surface of the cover element to support the Y-direction transfer mechanism; and an elastic element that presses the support structure against the cover element such that the support structure maintains contact with the upper surface of the cover element.
 2. The device according to claim 1, wherein the elastic element comprises a spring material.
 3. The device according to claim 1, wherein the support structure includes a roller that moves by rolling over the upper surface of the cover element.
 4. The device according to claim 3, further comprising an annular anti-vibration element that circumferentially covers an outer periphery of the roller.
 5. The device according to claim 3, wherein the support structure includes: a roller shaft that rotatably supports the roller; a support frame that supports both ends of the roller shaft; a first support shaft and a second support shaft each provided on a line of extension from the both ends of the roller shaft to allow the support frame to be moved up and down represented as a Z-direction.
 6. The device according to claim 5, wherein centers of the first and the second support shafts and the roller shaft respectively are collinear with an imaginary straight line, and wherein the imaginary straight line is parallel to a centroidal line which passes through a centroid of the Y-direction transfer mechanism and which extends in the Y-direction, the imaginary straight line and the centroidal line residing on a Y-Z plane. 